3 September is Labor Day. Everyone else in the world celebrates on 1 May. In Aprilof 1856, stonemasons in Melbourne protested in favor of the work day being reduced to 8 hours as suggested by the 8 Hour Movement (8 for rest, 8 for work, 8 for leisure). Previously, working 16 hours per day, 6 days per week was perfectly normal.

On 1 May, 1886 over 400,000 workers protested in favor of the adoption of the eight-hour-workday in the US. Government troops responded by opening fire, killing seven in Milwaukee, followed by the Haymarket Riots in Chicago three days later. There, a cop was killed and at least 4 workers as well when violence flared up between cops, scabs and protestors. Eight activists associated with the rally were sentenced to death. One commited suicide in his cell and four others were hanged. In 1893 the eight were pardoned. Of course, most had been dead for six years, so...

So, taking a page from the Christian Church, which successfully co-opted countless heathen holidays by re-branding them feast days and religious observations (e.g. Easter... in which a breeding rabbit carries eggs that symbolize... Jesus, and his, uh, hatching from the tomb-metaphorically speaking); Labor Day in the US was moved to September and became an end-of-summer holiday where observers have their last grill-outs of the year.